1. Field of the Invention
The present invention relates to a cooling method, a cooling system and a fan apparatus for cooling an electronic apparatus with air streams.
2. Description of the Related Art
Electronic elements such as a device module and a circuit board module are contained in an electronic apparatus such as a CPU cabinet of a computer system. Natural or forced air streams are let to enter the electronic apparatus, thereby cooling the electronic elements. FIG. 1 shows an example of a cooling structure in this type of conventional electronic apparatus.
As is shown in FIG. 1, the front face of a box body 10 is closed by a front cover 16. An air suction port 16a is formed in substantially the entire surface of the front cover 16. The rear face of the box body 10 is closed by a rear cover 17. An exhaust port 17a is formed in an upper part of the rear cover 17. A fan 22 is provided in an upper region on the rear side of the box body 10, at a position facing the exhaust port 17a. A plurality of electric elements 1 are situated within the box body 10 on the front side.
In this type of conventional electronic apparatus, air streams 2 introduced from the air suction port 16a pass through the electronic elements 1 to be cooled. Each air stream 2 divides into an air stream 2a going upward in the box body 10 and an air stream 2b going straight toward the rear in the box body 10. The air streams 2 introduced from the air suction port 16a in the front cover 16 are passed through the electronic elements 1 and exhausted via the exhaust port 17a to the outside as an exhaust air stream 3 by the fan 22 provided in the upper region on the rear side. Thereby, the electronic elements 1 are forcibly cooled by the air streams.
The above cooling system, however, has the following problem. The air stream 2a flows smoothly along the substantially straight line connecting the air suction port 16a and fan 22, and cools efficiently the front and middle parts of the electronic element 1 located in the course of the air stream 2a. However, the air stream 2b flows off the substantially straight line connecting the air suction port 16a and fan 22, and stagnates in a rear-side space 4 in the box body 10. Consequently, the rear part of the electronic element 1 located along the air stream 2b is not cooled efficiently.